Gearing and method of making the same



Feb 5 i924. 15432622 v H. J. SCHMICK GEARING AND METHOD OF MAKNG THE SAME Filed Jan. 20, 1922 4 Sheets-Sheet l g Jim ry j Jai/mdf.

Feb. 5 1924 EASZSZZ lH. J. SCHMICK GEARING AND METHOD OF MAKING THE SAME Filed aan. 2o, 1922 4 sheetsheet 2 Feb. 5 1924 3,432,622

H. J. sca-:MICK

GEARING AND METHOD OF MAKING THE SAME Filed Jan. 20. 1922 4 Sheets-Sheet 5 l l l l I l f l l l l l noauto@ ASZZZ Feb 9 H. J. SCHMICZK GEARING AND METHOD oF MAKING THE SAME Filed Jan- 20. 1922 4 Sheets-Sheet 4 H435 @Hoz nog@ Patented Feb. 5, i924.

unirse stares HENRY J'. SCHMUCK, 01E WILLAMSPORT, PENNSYLVAN.

GEARING AND METHOD 0F MKNG THE SAME.

Application tiled January 20, 1922. Serial No. 530,631.

To all whom t may co/noem Be it known that HENRY J. Solution, a citizen of the United States, residing at AlWilliams ort, in the county of Lycoming, 5 State of ennsylvania, has invented an Improvement'ir'Gea'ringand Methods of Making the Same, ot which the following description, in connection uwith the accompanying drawings, is a specification, like characw ters on the drawings representing like parts.

This invention aims to improve the ediciency and utility of gearing, more especially gearing having twisted teeth, suciias bevel, screw and worm gearing, and coml prises both -the gearing as a new article 'of manufacture and a novel method oit producing `gear teeth and screw threads.

'lliis invention diiers from and is an improvement upon gearing as heretofore pro- 2@ duced in combinin in one product both rolling and angulary sliding stepped movement to either hand relative to the direction or lead, thereby reversing and consolidating the eliect of the right and lefty hand 253 components of travel oftwisted gearing as heretofore made 'so as to reduce and eliminate the loss of eiciency and power due to the angularity'of the teeth.

Reference is made to my prior Patent No. 675,020,`dated May 28, 1901, for an explanation of the operation of stepped, dat contact surfaces in a radio-helical cam trom which one of the underlying principles ot operation of the cam-like engaging meansconstituting the working faces of the present invention may be understood.

Further aims and advantages of the invention appear hereinafter in connection with the description of the forms of screw or worm gearing and method ot producing the same selected tor purposes of illustration.

lln the dra-wings, Fig. 1 is a side view of a artly finished worm or screw gear embo ying the invention;

Fi 2 is a cross-section of the same on the line 2 2 in Fig. 1;

Figs. 3 to 8, inclusive, are a series of diagrams each simulating a development of a cylinder and having a series of cuts thereon illustrating independently and successivel by diminishing intervals of diderent simu taneously occurring movements that result in the product shown Fig. i;

lFig. 12 is a cross-section of a finished gear produced by the process described in coiinection with Fig. 7;

Fig. 13 is a side view of a nished gear iproduced by the process described in connection with Fig. 8.

Figs. la and 15 are side views ot specimen screw blanks illustrating for comparison the result of a very coarse angular and endwise spacing of the cuts and the effect of taking intermediate cuts spaced angularly but not endwise; and

Figs. 16, 17 and 18 are side views of specimen screw blanks out by the method illustrated in Figs. 5 and 7, showing the effect of diderent angular and lateral spacings of the cuts, the successive examples havingthe angular and lateral spacing diminished by one-half.

'lhe screw 11 embodying my invention,

which is illustrated in Figs. l and 2 in a C partly completed state, has working Jfaces 12, that are composed of a series or" narrow facets 18, reversed in angular direction on the two iaces, formed by cutting a succesf sion of grooves with straight bottoms and outwardly divergingv slanting side walls crosswise of the axis of the screw, successive grooves Vbeing spaced circumferentially around the screw and lengthwise ot the anis by rolling the screw at an angle to the normal to the axis ofthe cutter.

rlhis action may be better understood by referring to the diagrams, Figs. 3 to 8, vinelusive, each of which shows the development of a cylinder (shown in heavy dotted lines in Fig. 8) having its axis itt-B horizontal and movable in a horizontal plane back and forth in the direction of the double arrows C--C',and also capable ot adjustfidi@ ment in three directions or ways, first, angu- 'l larly;y second, endwise in the direction o'l B; and third,.s1dewise in the direction perpendicular to its airis as indicated bytheaiy.

' gg y incassa rows D. Assume that this cylinder is moved forward in the direction of the arrow C and under a cutter so as to make the cut 0 in Fig. 3, then back in the opposite direction C, and adjusted prior to taking a second cut `by rolling it 1n the direction of the arrows D on a pair of imaginary wheels (which in the illustrative example are somewhat larger in diameter than the cylinder itself) until it has yrotated through lli it isy again moved lforward to engage the cutter in the direction of the arrow C the resulting cut will be made in the location indicated by the numeral 1 in Fig. 3. Upon again adjusting the angular position of the cylinder by roll* ing it as before and making another cut 2 it will be spaced relatively to the preceding cuts as indicated in the diagram Fig. 3. lt the same cycle of operations be repeated, successive cuts 3, It, 5, 6, 7 and 8 will be made occupying relative positions around the cylinder as shown in the development, Fig. 3, in the direction of a left hand thread.

lf, in addition to adjusting lthe cylinder angularly by 'rolling it as described above, it is also adjusted axially in the direction of B an amount greater than its relative movement toward A due to its rolling, and suc.-

i cessive cuts are taken alter making both the an ular and axial adjustments these cuts wil occupy relative positions as shown, in Fig. @wherein the successive cuts are numbered 0, 1, 2, 3, 4, 5, 6, 7 and 8, and have the direction around the screw of a right hand ing the blank.

This edect is the resultant of the left hand component due to rolling the cylinder and the right hand component due to spacing it endwise of its axis, as is clear from an inspection of Fig. 5, wherein the cut numbered 1 was made following the out O after adjusting the cylinder by rolling as described in connection with Fig. 3 and the cut numbered 2 was made `following the cut 1 after adjusting 'the cylinder lengthwise toward B an amount somewhat greater than the compothread, just the reverse et the result of roll- 'nent of en-dwise movement due to rolling it. The successive odd numbered cuts were each made after a rolling adjustment and the intervening series of even numbere cuts were each made alter en endwiseadjustment of the cylinder.

lf the spacinar circumierentiall and axially he diminished by one half, t e two series of odd and even numbered cuts appreach'one another and the cuts in each series overlap to form a continuous groove, as shown in Fig. 6. lt this process of diminishing the secin be carried far enough it "f 1s evident t at t e two series of cuts will nearly coincide, approximating a dsingle groove winding around the cylinder in either a right hand or a left hand direction depending on the relative magnitude ot the left hand component due to rolling the cylinder and the ri ht hand component due to adjusting the cy inder endwise.

In Fig. 7, the individual cuts, instead ci being straight walled as in Figs. 3, 4, 5, and 6, have slanting sides, and the width ci the flat bottom and relative amounts of rolling movement and endwise movement are such as to cause successive cuts to'overlap circumferentially and axially when the cuts are taken first `after rolling and then after adjusting axially as described for Fig. 5.

In Fig. 8 the successive cuts are taken alter both a rolling and an axial adjustment of the cylinder,the same as shown in Fig. 4, except that the cuts have slant-ing sides in Fig. 8 instead of the straight sides of Fig. t. The resulting groove has similar but not identical `characteristics when both rolling and axial adjustment of the cylinder are made between successive cuts, as when they are made singly in alternation between cuts, as is indicated by a comparison of Figs. 7 and 8. 3

See also Figs. 12 and 13, wherein the latter shows a vear .16 produced by the process illustratec? in Fig. 8, and the former shows a similar gear 17 made by the process illustrated in Fig. 7. The dotted line 18 in Fig. 12 indicates the left hand direction of the thread due to rolling the blank.

The gear 19 shown in Fig. 11 has its working faces 20 formed by cuts taken at an angle approximately the same as 'the direction of their inner or base edges. The reversal o' the angle of the'lacets on opposite sides of 'the groove thereby formed is even more marked than in the case of the gear shown in F ig. i.

ln the 'illustrative specimens shown in Figs, la to 18, inclusive, the direction ot the angle made by the successive cuts is to the left, i. e., contrary to the direction ot lead, as clearl shown by com aring Fig. 17, tor enamp e, with Fig. 1. Fhis results in changing the direction of slope ofY the straight portions of the side walls or facets 30 with reference to the anis of the blank, which 'is advantageous for some purposes.

The specimen 31 shown in Fig. 14%: is produced by a cycle ci operations like that illustrated in Figs. 5 and 7, wherein the blank is alternately rolled and s aced between the successive cuts. Thespecimen 32 shown in Fig. 15 is produced 'by a cycle ol operations wherein the blank is cut and rolled four times in succession (each rolling being onctourth the angle of rolling in the reduction of the specimen 31 shown in Fig. lll and after the fourth cut it is shifted laterally the same distance as in the production of the specimen 31. Thesuccessive cuts are numbered from 1 on in each of these Figs. it and 15.

The specimen 33 shown in Fig. 16 is pro.

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duced-'by a simlar lcycle ot operations to that followed in producing the specimen 31, excepting that there are twice as many cuts, andthe amount of rollin and lateral shifting is one-half that used 1n producing specimen 31. Likewise the speclmens 34 and 35 l. spectively, in producing specimen 35 in comparison with the same cuts and movements in producing specimen 33. rlhese specimens, 33, 34 and 35, exemplify the characteristic4 features of the invention found in the specimens shown in 'Figs 1 and 11, and illustrate the fact that these characteristics are maintained as the number of cuts and ineness of the spacing are increased to the necessary degree to produce a sutliciently uniform surface for the product to have commercial utility.

Figs. 9 and 10 illustrate suitable apparatus tor producing screws by my improved method. The blank 21 is mountedl to turn on an arbor 22 which has its ends journaled in a sliding trame` 23 supported in a guide frame 24 on the table 25 of a suitable machine such as is described in my application idled December 31, 1921, Serial No. 526,327. The ends of the arbor 22 have gears 26 which roll on the racks 27 fixed to the guide .frame 2t. A screw 28 serves to adjust the slidin frame in the guide frame to rotate the ar or and blank. Lateral adjustment ot' ciprocating the table 'load and by the fact that their angle the guide frame and blank may be secured by the usual cross feed screw with which the table is fitted. The blank is caused to move back and forth under the cutter 29 by re- 25, thereby making the successive cuts.

Gears made in accordance with my im` proved method are characterized b the easeVA with which they turn under a eavy lead is constant from top to bottom, i. e. the angle madeby their side walls with rep'ect to the parallel planes parallel to the irection of the axis and the direction of cut at any point is the same at all points of said cut, irrespective of the distance from the axis. Hence twisted gears and screws embodyin the invention can be made to roll to ether lke gears and move lengthwise re ative' to each other like screws.

.The invention is not restricted to any particular forms and dimensions of screw, nor to the particular means for making screws shown and described.

ll claim the following `as my invention:

1. A twisted gear tooth having its side walls making a constant angle from top to bottom with reference tothe anis of the gear other than the angle of lead.

2. A. twisted gear tooth having its side walls making a constant angle of ead from top to bottom, said angle being reater or less than a right angle as desire irrespective ofthe amount and direction ot lead.

3. A. screw of the character described adapted to roll together with a screw of like angle of side wall of the same hand.

t. A screw of the character described adapted to roll and slide lengthwise in engagement with a mating screw ot the same hand.

5. The method of producing twisted gears by successive cuts transverse to the axis comprising rolling the blank between cuts to displace it bodily in a direction at an angle to the direction of the cut.

6 The method of producing twisted gears by successive cuts transverse to the axis, comprising rollin the blank between cuts to displace it bo ily sidewise and endwise in a direction at an angle to the direction of the cut and adjusting it endwise ot the axis of the cutter in the direction opposite to its endwise movement due to rolling.

7. lhe method ot producing twisted gears, by successive cuts transverse to the axis, cornprising rollin the blank between cuts to' displace it bo ily sidewise and endwise in a direction at an angle to the direction ot the cut and adjusting it endwise of the axis of the cutter in proportion to the amount of displacement due to its rolling movement.

8. The method of producin twisted gears of the character described gy a series of overlapping cuts, comprising rolling the blank at a predetermined angle to the direction of cut to produce combined movement of rotation and translation and maintaining a predetermined ratio of rotation to movement of translation.

9. rlhe method ot producing twisted gears by simultaneously rolling the blank between successive cuts to move it bodily sidewise and endwise in a direction at an an le to the direction of the cut and spacing 1t aaially to counteractV the endwise movement due to rolling.

10. The method of roducing twisted gears by alternately'rol ing the blank between successive cuts to move it bodily sidewise and endwise in a direction at an angle to the direction ot the cut and adusting it endwise ot the axis ot the cutter m the direction opposite to its endwise movement due to rolling.

11. The method ot producing a twisted gear of the character described by inter,- mittent combined rotation and translation simultaneously in two directions, substantially 'as described.

12. Twisted gearing ot the character described comprising pairs of facets on their itl liti

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llilll lltlli opposite working faces having reversed angular inclination and parallel direction with reference to a common line transverse to their axis of rotation.

13. The method of producing a series 'of twisted grooves on a blank having a surface of revolution by means of a series of cutters 'that comprises reciprocating said blank transversely of the cutters to make a series of parallel cuts in its periphery, said blank being mounted to rotate and move bodilyv at right angles to its axis between ,cuts for indexing 'and the axis of said blank being held at an obtuse angle to the direction ofcut, whereby indexing movement rotates and shifts said blank'axially with reference vto said cutters and successive cutsA are displaced axially and circumferentially to merge in .a plurality of grooves having side Walls formed in opposite disposed corresponding facets symmetrica about a transverse line making the same angle with the axis of the blank as the angle of said blank with the direction of cut.

14. The method of producinur a twisted groove on a bl'ank having a surf-ace of revolution by means of a cutter that comprises reciprocating said blank transversely of the cutter to make a cut'in its periphery, said blank being mounted to rotate and move bodily at cuts for indexing and the axis of said blank being held at an obtuse angle to the direction of cut, whereby indexing movement rotates and shifts said blank axially with reference to said cutter and successive cuts are displaced axially and circumerentially r1ght angles to its axis between l whereby in operati/on said gearing will toVA mer in a groove having side walls formed m oppositely disposed corresponding facets symmetrical about a transverse line making the same angle with the axis of the blank as the angle of said blank with the direction of cut and having a stepped relationship in the direction of lead.

15. .Gearing comprising mating ars having twisted teethy with vside wal s characterized by oppositely inclined straight strips grouped in pairs and constitutin Working surfaces, the strips ofeach pair s opin one up and 'the other down the sides o the teeth on opposite sidesof the axis and having a transverse direction of slope at an angle with the axis ater or less than a right angle, Whereb 1n operation said ears wil partly roll an partly slide in an out of engagement.

16. Gearing comprising mating gears having twisted teeth with side walls characterized by oppositely inclined straight strips angularl disposed in offset stepped relation an merging along non-intersecting lines forming warped surfaces about the axes of rotation thereof said dat strips being grouped in pairs ci cam-like engaging means each having a-slope at an -angle to the axis and lying in a plane intersecting the plane of its mate in a line at an angle to the axis greater or less than a right angle,

partly slide and partly roll in and out of engagement.

ln testimony whereof, l have signed my name to this specication.

HENRY J. SCHMICK. 

